The present invention relates in general to steam engines, and more particularly to an arrangement for controlling the actuation of the inlet valves for the cylinders of a steam engine.
In the patent to Marion K. Harris, No. 3,572,215, issued on Mar. 23, 1971, for Single Acting Steam Engine, there is disclosed a steam engine in which the inlet valves for the cylinders are opened by the movement of a separate cam located on the output shaft of the engine. Such valve-actuating arrangements were particularly adapted to the mushroom poppet valve. The mushroom poppet valves in steam engines do not lend themselves to be located in the cylinder head to reduce steam inlet passage length to a minimum for facilitating filling of the cylinders with live steam.
Impulse valves have been disposed in the cylinder head. However, such impulse valves have been actuated by attaching a fixed, rigid stud to the top of the piston. This arrangement is limited in that only a valve event symmetrical with the top dead center can be achieved. Thus, either the valve opening lead before top dead center must be too long for good low running speed or the cutoff after top dead center must be very short, thereby limiting specific output.